Key-lever tension for typewriters



May 26, 1925. A 1,539,172

- H. ELLIS I KEY LEVER TENSION FOR TYPEWRITERS Ofiginal Filed i 5,1919

Patented May 26, 1925.

UNITED STATES- HALCOLM ELLIS, OF NEWARK, NEW JERSEY.

KEY-LEVER TENSION FOR TYPEWRITERS.

Original application filed February 5, 1919, Serial No. 275,118. Dividedand this application filed February 19, 1923.

To all whom it may concern.

Be it known that I, HALcoLM ELLIs, a citizen of the United States,residing at Newark, in the county of Essex and State of New Jersey, haveinvented certain new and useful Improvements in Key-Lever Tensions forTypewriters, of which the following is'a specification.

This invention relates to tensioning means for the key levers oftypewriters, and the present application is a division of my applicationSerial No. 275,118, filed Feb. 5, 1919, now Patent No. 1,416,338, datedFebruary20, 1923.

The present improvements enable the returning springs of the key leversof a typewriter to be simultaneously tensioned by a simple andconvenient operating device to suit the touch of the user, therebyenabling the user of the machine to change the tension of all the keylever returning springs at will and so that the tension on all of thesprings is substantiallythe same. i I

A practical embodiment of my invention comprises independent suspensioncoil springs, one for each of the key levers, a movable member to whichsaid springs are connected, and adjusting means, such, for

instance, as a thumb screw, for moving said member to vary the tensionon the springs.

Vhile the present improvements are illustrated in connection with atypewriter, such as disclosed in my patent aforesaid, this is done forthe purpose of disclosing a practical embodiment of the invention andrelationship to the parts of a typewriter and not by way of limitationof the invention as the latter may he used on any typewriter employingpivoted key levers.

The invention is susceptible of modification and is not limited to thespecific cmbodiment described hereinafter and disclosed in the drawing.

The accompanying drawing is a vertical longitudinal section through atypewriter provided with my present improvements.

The key levers, of which there are four different lengths, as usual, areshown at 1. The key levers are pivoted on a wire 2 extending across themachine at the rear and are held in normal, raised, position by suitablesuspension contractile coil springs 3,

one for each key lever.

A swinging plate 4 is hinged on the back Serial No. 620,089.

rail 5 of the typewriter frame in any suitable manner, for instance, asshown at 6.

The upper ends of the respective springs 3 are hooked over and suspendedfrom a single red 7' which extends across the rear of the machine and iscarried by the swinging plate, 4. A thumb screw 8, which bears on theback rail 5, has a screw threaded engagement at 9 with a member carriedby the swinging plate 4.

On'turning the thumb screw 8 in one direction, the swinging plate 4 willswing toward the left, thereby diminishing the tension on the suspensioncoil springs 3. When the thumb screw 8 is turned in the oppositedirection, it will draw upon the swinging plate 4 and swing the lattertoward the right, thereby increasing the tension on the suspension coilsprings 3.

My invention does away with the necessity of independently adjusting thetension of the returning spring of each key lever of a typewriter andaffords means by which the user can instantly regulate the tension tosuit the individual touch of the user.

In the machine illustrated, the type bars are shown at 10 as pivoted onthe wire 11 in the shiftablc type basket 12 which is raised by the arm13 carried by shaft 11 and operated by one or the other of two shiftkeys 15 of which only one is shown. The connection between therespective key levers 1 and type bars 10 comprises a bell crank lever 16pivoted at 17 and having a slot and pin connection at 18 with the keylever 1. A link 19 pivoted to the type bar 10 at 20, is hooked over apin 21 on the bell crank lever 18.

\Vhat I claim is In a typewriter, the combination with its frame. andkey lovers, of a swinging plate hinged on the frame and disposed abovethe key lovers, :1 single rod carried by said plate above, and crosswiseof, the key levers, suspension coil springs connecting said rod to theseveral key levers, and an adjusting HALCOLM ELLIS.

